The purpose of this study is to to determine the effect of work discipline, work environment, and work stress on employee performance of PT Enseval Putra Megatrading Purwokerto. This study used quantitative research method. The sampling method in this study used the saturation/census method. The population in this study are employee of 65 respondents. The data analysis technique used is multiple linier regression analysisi. The result of the analysis showed that work discipline and work environment partially did no effect employee performance, and work stress has pocitif significant effect on performance of PT Enseval Putra Megatrading employees. Furthermore, the result showed that work discipline, work environment, work stress simultaneously have a significant effect on employee performance.